scholarly journals Tyrosine aminotransferase induction in hepatocytes cultured from rat foetuses treated with dexamethasone in utero

1979 ◽  
Vol 180 (3) ◽  
pp. 545-549 ◽  
Author(s):  
G C T Yeoh ◽  
T Arbuckle ◽  
I T Oliver
Keyword(s):  
Culture Medium ◽  
Actinomycin D ◽  
Tyrosine Aminotransferase ◽  
In Utero ◽  
Aminotransferase Activity ◽  
Foetal Liver ◽  
Translational Block ◽  
Cells Cultured ◽  
Specific Mrna

1. The administration of dexamethasone to foetal rats in utero does not result in the appearance of specific tyrosine aminotransferase activity even after 24 h. 2. When foetal hepatocytes are cultured in vitro from animals treated in utero with dexamethasone, significantly higher activities of specific tyrosine aminotransferase are found than in untreated controls. 3. Dexamethasone in vitro induces specific tyrosine aminotransferase in cells cultured from control animals and the effect is maximal at 10 nM in the culture medium. 4. Actinomycin D at 0.2 microgram/ml in the culture medium completely prevents the induction of activity in vitro. 5. In cultures established from animals treated with dexamethasone in utero, the increase in specific tyrosine aminotransferase activity over the control cultures is only marginally decreased in the presence of actinomycin D. 6. The results can be interpreted to mean that dexamethasone in utero stimulates the transcription of enzyme-specific mRNA, which is not rranslated until a translational block in the foetal liver is removed by the conditions of culture in vitro.

scholarly journals The effect of cytosine arabinoside and bromodeoxyuridine on the appearance of tyrosine aminotransferase in cultured foetal hepatocytes of the rat

1980 ◽  
Vol 188 (3) ◽  
pp. 929-932 ◽  
Author(s):  
G C Yeoh ◽  
I T Oliver
Keyword(s):  
Cell Differentiation ◽  
Rat Liver ◽  
Cytosine Arabinoside ◽  
Culture Medium ◽  
Tyrosine Aminotransferase ◽  
Aminotransferase Activity ◽  
Inhibitory Effects ◽  
Foetal Liver ◽  
Foetal Rat

1. The acquisition of dexamethasone-inducibility of tyrosine aminotransferase activity by hepatocytes cultured from 15-day-foetal rat liver is blocked in the presence of cytosine arabinoside. 2. Similar results are obtained in the presence of bormodeoxyuridine. 3. No effects on steroid-inducibility of tyrosine aminotransferase are obtained with either of the above compounds in hepatocytes cultured from 19-day-foetal liver. 4. the inhibitory effects of the agents are substantially reversed after their removal from the culture medium. 5. The effects of bromodeoxyuridine suggest that cell differentiation, with respect to tyrosine aminotransferase-inducibility, occurs in cultures of 15-day-doetal hepatocytes. 6. The effects of cytosine arabinoside suggest that such an event is dependent on mitosis.

scholarly journals Role of adrenaline and cyclic AMP in appearance of tyrosine aminotransferase in perinatal rat liver

1980 ◽  
Vol 190 (3) ◽  
pp. 685-690 ◽  
Author(s):  
A V Ghisalberti ◽  
J G Steele ◽  
M H Cake ◽  
M C McGrath ◽  
I T Oliver
Keyword(s):  
Cyclic Amp ◽  
Culture Medium ◽  
Actinomycin D ◽  
Cultured Cells ◽  
Tyrosine Aminotransferase ◽  
Newborn Rats ◽  
Aminotransferase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Old Rats

1. Adrenaline increased hepatic tyrosine aminotransferase activity when injected into foetal rats or 2-day-old rats. 2. The inhibition of the postnatal increase in tyrosine aminotransferase activity which occurred in adrenalectomized newborn rats rapidly overcome by injection of adrenaline or dibutyryl cyclic AMP. 3. The effects of adrenaline or dibutyryl cyclic AMP on the tyrosine aminotransferase activity in foetal, adrenalectomized newborn and 2-day-old rats could be partially or completely blocked by prior treatment with actinomycin D. 4. Dibutyryl cyclic AMP induced tyrosine aminotransferase activity in hepatocytes cultured from 15-day foetal rats in glucocorticoid-free medium. 5. Actinomycin D at 0.2 microgram/ml in the culture medium completely prevented the induction of tyrosine aminotransferase activity by dibutyryl cyclic AMP in cultured cells. 6. The results suggest that adrenaline and cyclic AMP stimulate a transcriptional event during induction of tyrosine aminotransferase in perinatal liver.

scholarly journals Factors affecting the premature induction of tyrosine aminotransferase in foetal rat liver

1968 ◽  
Vol 108 (2) ◽  
pp. 333-338 ◽  
Author(s):  
P. G. Holt ◽  
I. T. Oliver
Keyword(s):  
Actinomycin D ◽  
Tyrosine Aminotransferase ◽  
Premature Delivery ◽  
Aminotransferase Activity ◽  
Foetal Development ◽  
Factors Affecting ◽  
Foetal Liver ◽  
Amino Acid Analogues ◽  
Lag Period

1. Premature delivery of foetal rats by uterine section results in the rapid appearance of tyrosine aminotransferase activity in foetal liver, after an initial lag period of 3–6hr. 2. The premature induction of activity is completely repressible by actinomycin D given soon after delivery and partially repressible by puromycin and amino acid analogues. 3. Glucagon injections into foetal rats in utero lead to production of tyrosine aminotransferase in the foetal liver, but adrenalin and nor-adrenalin are without effect. 4. Injections of glucose, galactose, fructose and mannose into prematurely delivered rats repress the development of tyrosine aminotransferase activity about 50% when they are given 2hr. after delivery, but glucose has no significant effect when injected at delivery. 5. The results are discussed in relation to current hypotheses on the role of hormones in enzyme induction in foetal development.

scholarly journals The effects of salicylate on the activity of rat liver tyrosine–2-oxoglutarate aminotransferase in vitro and in vivo

1972 ◽  
Vol 126 (2) ◽  
pp. 347-350 ◽  
Author(s):  
A. A.-B. Badawy
Keyword(s):  
Rat Liver ◽  
Pyridoxal Phosphate ◽  
Actinomycin D ◽  
Sodium Salicylate ◽  
Intraperitoneal Administration ◽  
Tyrosine Aminotransferase ◽  
Major Effect ◽  
Endogenous Activity

1. Salicylate, in concentrations of 0.25mm and above, enhances the basal activity of tyrosine–2-oxoglutarate aminotransferase in homogenates of rat liver incubated in the absence of added pyridoxal 5′-phosphate (endogenous activity). The effect is decreased by increasing the concentration of the cofactor. 2. The intraperitoneal administration of sodium salicylate enhances the activity of rat liver tyrosine aminotransferase; the major effect during the first hour being on the enzyme in the absence of added pyridoxal phosphate. Actinomycin D prevents the induction of the enzyme by cortisol and tryptophan. Induction by pyridoxine or salicylate is 50% inhibited by actinomycin D. The effects of the injections of various combinations of cortisol, pyridoxine and salicylate were also studied in the absence or presence of actinomycin D. 3. It is suggested that salicylate induces rat liver tyrosine aminotransferase by displacing its protein-bound cofactor and that a cofactor-type induction of the hepatic enzyme occurs in pyridoxine-treated rats.

scholarly journals Biphasic effect of acute ethanol administration on rat liver tyrosine-2-oxoglutarate aminotransferase activity

1980 ◽  
Vol 186 (3) ◽  
pp. 755-761 ◽  
Author(s):  
A A B Badawy ◽  
B M Snape ◽  
M Evans
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Actinomycin D ◽  
Tyrosine Aminotransferase ◽  
Ethanol Metabolism ◽  
Ethanol Administration ◽  
Aminotransferase Activity ◽  
Biphasic Effect ◽  
Initial Decrease ◽  
Acute Ethanol

1. Acute ethanol administration causes a biphasic change in rat liver tyrosine aminotransferase activity. 2. The initial decrease is significant with a 200 mg/kg dose of ethanol, is prevented by adrenoceptor-blocking agnets and by reserpine, but not by inhibitors of ethanol metabolism, and exhibits many of the characteristics of the inhibition caused by noradrenaline. 3. The subsequent enhancement of the enzyme activity by ethanol is not associated with stabilization of the enzyme, but is sensitive to actinomycin D and cycloheximide. 4. It is suggested that the initial decrease in aminotransferase activity is caused by the release of catecholamines, whereas the subsequent enhancement may be related to the release of glucocorticoids.

Polysaccharides in the culture medium of cotton cells cultured in vitro

1987 ◽  
Vol 1 (5-6) ◽  
pp. 359-363 ◽  
Author(s):  
A.J. Buchala ◽  
T. Genoud ◽  
H. Meier
Keyword(s):  
Culture Medium ◽  
Cells Cultured

scholarly journals Early studies on the effect of peptide growth factor phytosulfokine-α on Brassica oleracea var. capitata L. protoplasts

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Agnieszka Kiełkowska ◽  
Adela Adamus
Keyword(s):  
Brassica Oleracea ◽  
Shoot Regeneration ◽  
Liquid Culture ◽  
Culture Medium ◽  
Breeding Lines ◽  
Liquid Culture Medium ◽  
Peptide Growth Factor ◽  
The Media ◽  
Cells Cultured

<span>Phytosulfokines (PSK) are peptidyl growth factors with the potential of inducing cell proliferation. We examined the effect of supplementation of liquid culture medium with 0.1 µM phytosulfokine-α (PSK-α) on protoplast viability and division frequencies in seven accessions of <em>Brassica oleracea</em> var. <em>capitata</em> L., including cultivars and breeding lines. Protoplasts were isolated from leaves and hypocotyls of in vitro grown plants and immobilized in calcium-alginate layers. Cabbage protoplast-derived cells cultured in medium supplemented with 0.1 µM of PSK-α had higher viability and division frequencies compared to cells cultured in PSK-α-free control medium. The effect of PSK-α was more pronounced in low-responding accessions (‘Sława z Gołębiewa’, ‘Ramkila F1’, LM, and LM98); however, in two cultivars with very low response (‘Badger Shipper’ and ‘Oregon 123’), although the division frequencies in the media supplemented with PSK-α were increased over the control, the differences were not significant. Obtained callus colonies were subjected to regeneration. PSK-α supplemented into the liquid culture medium had an indirect effect on shoot regeneration by inducing sustained cell divisions leading to an increase in shoot regeneration in Sława z Gołębiewa and both breeding lines.</span>

The Effect of Some Natural Cytotoxic Peptides on Tumor Cells

2018 ◽  
Vol 69 (3) ◽  
pp. 597-601
Author(s):  
Bogdan Mihail Diaconescu ◽  
Daniela Jitaru ◽  
Mihaiela Loredana Dragos ◽  
Magda Badescu ◽  
Teodor Stefanache ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Culture Medium ◽  
Actinomycin D ◽  
Tumor Cell Lines ◽  
Cytotoxic Effects ◽  
Cecropin A ◽  
Viability Study ◽  
Tumor Cell Culture ◽  
Natural Peptides

Many studies have highlighted the anti-tumor properties of some natural peptides known to have antimicrobial virtues. In this study, we evaluated the tumoricidal potential of dermaseptin, defensin, cecropin A and B on tumor cell lines: M14K (human mesothelioma). The viability study was performed using PE V Annexin and 7-AAD (7-amino-actinomycin D) (BD Pharmingen). This test was used to detect and measure apoptosis by flow cytometry technique. The experimental results of our study revealed that the cytotoxic effects of the four peptides depend on their concentration. In this in vitro experimental study, we found that the cytotoxic effect of the four cytotoxic peptides used depended on their concentration in the tumor cell culture medium, being significant at concentrations of 120mM and maintained at concentrations of 60�M. At 30�M concentrations these tumoricidal effects were insignificant. Of all the studied peptides, dermaseptin has the most powerful effect and the weakest effect b - defensin - 1.

scholarly journals The adaptive behaviour of isoenzyme forms of rat liver alanine amino transferases during development

1972 ◽  
Vol 128 (2) ◽  
pp. 403-413 ◽  
Author(s):  
Keith Snell ◽  
Deryck G. Walker
Keyword(s):  
Cyclic Amp ◽  
Rat Liver ◽  
In Utero ◽  
Adaptive Behaviour ◽  
Intragastric Administration ◽  
Aminotransferase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Neonatal Development ◽  
Foetal Liver ◽  
Glyoxylate Aminotransferase

1. The activities of the mitochondrial and cytosol isoenzyme forms of l-alanine–glyoxylate and l-alanine–2-oxoglutarate aminotransferases were determined in rat liver during foetal and neonatal development. 2. The mitochondrial glyoxylate aminotransferase activity begins to develop in late-foetal liver, increases rapidly at birth to a peak during suckling and then decreases at weaning to the adult value. 3. The cytosol glyoxylate aminotransferase and the mitochondrial and cytosol 2-oxoglutarate aminotransferase activities first appear prenatally, increase further after birth and then rise to the adult values during weaning. 4. In foetal liver the mitochondrial glyoxylate aminotransferase and the cytosol 2-oxoglutarate aminotransferase activities are increased after injection in utero of glucagon, dibutyryl cyclic AMP (6-N,2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate) or thyroxine. The cytosol glyoxylate aminotransferase and the mitochondrial 2-oxoglutarate aminotransferase activities are increased after injection in utero of cortisol or thyroxine. 5. After birth the further normal increases in the mitochondrial and cytosol 2-oxoglutarate aminotransferase activities can be hastened by cortisol injection, whereas the increase in cytosol glyoxylate aminotransferase activity requires cortisol treatment together with the intragastric administration of casein. 6. The results are discussed with reference to the metabolic patterns and the changes in regulatory stimuli (hormonal and dietary) that occur during the period of development.

scholarly journals Induction by growth factors of polysaccharide synthases in bean cell suspension cultures

1983 ◽  
Vol 210 (2) ◽  
pp. 509-515 ◽  
Author(s):  
G P Bolwell ◽  
D H Northcote
Keyword(s):  
Cell Cycle ◽  
Growth Factors ◽  
Cell Division ◽  
Culture Medium ◽  
Actinomycin D ◽  
Cell Suspension Cultures ◽  
Suspension Cells ◽  
Membrane Bound ◽  
Total Membrane ◽  
Specific Mrna

Suspension cells of bean subcultured into medium that maintains the culture and stimulates cell division but not differentiation brings about an increase in arabinan synthase activity. Subculture into a medium that induces both cell division and xylogenesis brings about in addition an increase in xylan synthase. Both synthases are membrane-bound and are concerned with the formation of neutral pectin or hemicellulose of the cell wall respectively. During the rising phase of the induction of these activities in the appropriate culture medium, the increases in activities were inhibited by either actinomycin D (an inhibitor of transcription) or D-2-(4-methyl-2,6-dinitroanilino)-N-methylpropionamide (an inhibitor of translation). Thus the control for the induction of the enzyme activities involves transcription and possibly translation. Subculture of the cells brought about an increase, probably non-specific, in total membrane-bound translation, as indicated by increased amounts of bound polysomes and incorporation of [35S]methionine into membrane proteins. If the control of the appearance of specific mRNA molecules is partially effected by growth factors then these are probably operative during the period of the cell cycle that is stimulated by subculture and it is probably at this time that the growth factors act to bring about the changes necessary for differentiation.

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